Method of producing volute springs from metal ribbons or the like



W. DREWITZ. METHOD OF PRODUCING VOLUTE SPRINGS FROM METAL RIBBONS OR THE LIKE.

APPLICATION FILED SEPT. B, 1920.

Patented Apr. 11, 1922.

UNITED STATES PATENT OFFICE.

WALTER DREWITZ, OF ESSEN, GERMANY, ASSIGNOR TO FRIED. KRUPP AKTIEN- G-ESELLSCHAFT, OF ESSEN-ON-THE-RUHR, GERMANY.

METHOD OE PRODUCING VOL-UTE SPRINGS-FROM METAL RIBBONS OR THE LIKE.

Specification of Letters Patent.

. Patented Apr. 11, 1922.

Application filed September 8,1920. Serial No. 408,963.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STAT. L, 1313.)

residing at 25 Fulienstn, Essen, Germany, a

citizen of the German Republic, have in vented a certain new and useful Improve ment in Methods of Producing Volute Springs from Metal Ribbons or the like, (for which I have filed applications in Germany, filed January 31, 1914, under Serial No. K. 57662 1/70; Austria, filed November 16, 1914, Patent No. 72372; Hungary, filed November 19, 1914, Patent No. 69431; Italy, filed overnber 18, 1914, Patent Reg. Atti. Vol. 440 No. 203; Switzerland, filed November 14,1914, Patent No. 69818; Holland, filed November 14, 191.4. Patent No. 1049. of which the following is a specification.

The subject matter of the invention comprises a method for producing volute springs such as for instance truncated cone springs from flat metal ribbons, in particular steel ribbons or fiat bars, which prevents the warpin or curving of the ribbon in a direction transverse to its longitudinal axis after the spring has been wound. This curvature is prevented according to. the present invention by turning up both longitudinal ribbon edges in the same direction when the ribbon is straight. hen the ribbon is then coiled up into the form of the spring desired, with the concave surface of the ribbon facing the mandril, on which the spring is wound, the curved edges will straighten out. I

M improved method is illustrated in the accompanying drawings in which,

Figure 1. is a side elevation of the metal ribbon beforeit is wound. V

Figure 2, is a transverse section" on line 2--2 Figure 1, seen from the right hand side and in larger scale, and

Figure 3 shows the finished spring in longitudinal vertical section.

As an example a truncated cone spring such as is shown in Figure 3 has been chosen to illustrate my invention. It is obvious that if, in winding such spring, the edges of the ribbon should curve outward during the winding the free action of such a spring would be seriously impaired.

In producing a spring which has perfectly parallel convolutions such as is shown in Figure 3, the ribbon A, Figure 1 is used after its longitudinal edges are upturned to a suitable extent such as is shown in Figure 2. The ribbon is then wound in the well known manner on a mandril, (not shown here) with the concave surface of the ribbon facing the mandril. The stresses produced during the winding, which heretofore have caused an outward curvature of the ribbon edges will straighten out the inward curvatures of the ribbon, so that when the spring is finished the sides will be straight as is shown in Figure 3. In certain instances it may be of advantage not only to curve the edges of the ribbon but to curve the entire ribbon transversely.

1 claim:

The method of producing volute springs from, ribbon metal, consisting in turning up to a suitable extent both longitudinal ribbon edges in the same direction when the ribbon is straight and then winding the ribbon into the desired spring shape with the concave ribbon surface facing the mandril, for the purpose set forth.

The foregoing specification signed at Essen, Germany, this 2nd day of June, 1920.

VALTER DRElVITZ.

In presence 0f-- HANs GoTrsMANN, Josnr ALBERTZ. 

